1, 3, 5-triazines as stabilizing agents for silver-halide emulsions



July 19, 1949.

' DERSCH 2,475,535 1, 3, 5-TRIAZINES'AS STABILIZING AGENTS FOR 7 SILVER-HALIDE BMULSIONS I 7 Filed Nov. 18, 1947 LIGHT SENSITIVE EMULSION LAYER COLLOIDAL LAYER CONTAINING A l,3,5-TRIAZINE 'I :IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIa SUPPORT COLLOIDAL LAYER CONTAINING Al,3,5-TRIAZINE F I 2 LIGHT SENSITIVE LIGHT SENSITIVE EMULSION LAYER SUPPORT COLLOIDAL LAYER CONTAINING l,3,5-TRIAZINE LIGHT SENSITIVE EMULSION LAYER CONTAINING A I,3,5-TRIAZINE SUPPORT INVENTOR FRITZ DERSCH ATTO R EYS Patented July 19, 1 949 1,3,5-TRLIAZINES AS STABILIZING AGENTS FOR SILVER-HALIDE EMULSION S Fritz Dersch, Binghamton, N. Y., assignor to General Aniline & Film Corporation, New York,- 1

N. Y., a corporation of Delaware Application November 18,1947, Serial No;'l8 ,6,643 Y l 1 11 Claims.

This invention relates to the stabilization of light-sensitive silver-halide emulsions, and particularly to the use of substituted 1,3,5-triazines as stabilizers for silver-halide emulsions.

It is knownthat light-sensitive emulsions, such as gelatin silver-halide emulsions, have a decided tendency to fog. The fog maybe of two types, namely, yellow fog and chemical (gray) fog. The yellow fog, sometimes referred to as color fog or 'dichroic fog, is essentially a colloidal deposit of silver, the color intensity and general appearance of which are determined by the minute particle size and degree of subdivision. The fog is chiefly yellow in color and is most apparent in the lighter portions of a negative. The color may vary, howi ever, and the colloidal silver particles may, for example, appear-green by reflected light and yellow or red by transmittedlight. The so-called chemical fog, or gray fog, on the other hand, is the more common and is formed in a number of ways. It may be caused by premature exposure, by excessive ripening of the emulsions, or by the storage of the film, particularly at high temperatures or for unusually long periods of time.

It is also known that mercapto tetrazoles and tetrazoles containing at least one =NH group, the hydrogen atom of which is capable of substitution by silver,.h ave been described as being effective in preventing an increase in fog and thus stabilizing or controlling the keeping quality. of light-sensitive silver-halide emulsions. Although these compounds have the ability to give to the emulsions to which they are added, greater stability and a steeper gradation, they have a definite shortcoming in that they, to some extent, lower the sensitivity Of the emulsions.

Theprimary object of the present invention is to provide stabilizers or fog inhibiting agents which tend to prevent the formation of chemical fog in light-sensitive silver-halide emulsions.

A further object is to provide stabilizers or antifogging agents for light-sensitive silver-halide emulsions, which do not lower the sensitivity of the emulsion, and which increase its stability.

Still further objects and advantages will appear fromthe following specification.

I have found that the ,aboveobjects are accomplished by the use" of substituted 1,3,5-triazines which do not contain an =NH group in their configuration, the hydrogen atom of which is capable of substitutionby silver, and which are superior to the tetrazoles heretofore employed. The sub- I stituted 1,3,-5-t riazines utilized in accordance with.

the present invenjtionlare characterized by; the following structural formulaz'pj-l I I ,l;,,.

, :L R, g wherein R represents an amino or methylamino group Ri represents an amino, methylamino, or

mercapto group; and Ra represents an amino or methylmercapt gro The following examples will serve to illustrate certainways in which the-stabilizers ofmy invention are prepared and applied,-but are not tobe construed as limiting the invention.

-, Example] 7 N=o 1 z Example II j i aj qm :ij jjnac GREEN-iii: y

2-methylmercaptori,dediniethylamino-l,fifi-triazine 2 grams of trithiocyanuricacid;trimethyl ester were treated with'5.2 cc.. (inslightgexcess) of a" 33% aqueous solutionof methylamine in a bomb at C. for 6 to s-hours, and the reaction mixture allowed to cool to room temperature; The mixture was then heated gently on a steam bath to drive off methylmerca'ptan and the residue dissolved in 5 to 10 cc. of concentrated hydrochloric acid. To'this solution,- water waszadded. slowly I until no further precipitateformed; "The solution wasfiltered and the" filtrate concentrated on a steam bath tol a small volume, neutralized with ammonium hydroxide and then dried. The dry product was washed with water to remove ammonium chloride, dissolved in 0.001 N H01 and then concentrated to a solid. The solid was recrystallized from boiling water.

' Example 2-metn 1merca to-4,e-aismino-iyat-triaain 2 grams of trithiocyanuric acid trimet hyl ester were digested in a bomb with (20. (in excess) of alcoholic ammonia for 5 hours at 160 C. The reaction mixture was cooled to room temperature r'a'ct was cooled, tered and concentrated to dryness.

Beneficial efiects in gray fog reduction may be obtained when solutions ,of these substituted 1,3,5-triazines are incorporated in the silver-halide emulsions as rifierii'ng finals or as coating finals." By ripening final is meant an addigftior sensit ivityiiiaking process. d to iricrease the names; an n list prior to coat- (g1ass, filrn, etc.)

mum sensitivity" e urictioi's of these coating finals are nearly 't'he 'same as those of the ripening finals, 1.19., to increase sensitivity or to minimize fog formation,

When used as ripening finals, the substituted 1,3,5-triazines are best u sed'in a concentration of 1 s to mgs. per Kilogram of wet emulsion, and when used as coating finals in a concentration of 1-50 mgs per kilogf w t mulsionr N in to The gained when (l:ohtair ing substioce'ssedafterst'anding There isja marked rep'red; itha processed n ith' n jo added substidvahtag'es"seem to um loss'o'f sensi- The method of testing'thestabilizers employed in the following examples consists of coating two film strips, such "as cellulose acetate, with the same emulsion, one 'with and one without any stabilizer, storing the einfilsiohs in an incubator for six days at 50 "C.,:tfien exposing, developing, fixing, and washing the same under standard conditions. "I'h 0g density or blackening producdinith "'ia's in the two emultransmission densi- The following xenr i ill-"serve toiillustrate certain'ways in which tlie'stabiliz ers" of my inventitn have beeneepned.

, ,qs'iishtwgasticmesses-d with si -or nary sions.

. bt'ained its maxi- 7 States Patents 1939322 Example Ivswas again repeated with the exception that 8 mgs. of 2-methylmercapto-4,6- diamino-1,3,5-triazine was substituted for 5 mgs. of 2,4-diamino-6-mercaptq-1,3,5 t incubation anddvl tlf taini ngZ-m'etI'iyTfife d mii'io triazine "gave are Further expenm ts l1 qualities (i. -e;, 'a'reduction-i'ntheiog incubation.orbylong'storaigel, b'u't diminished and, inSUfiIe C8s'sc0iiip1fe'1y" nated changes 'ofr'speed to which sorn'e emissions are susceptible.

The stabilizers, which-I 'ihaiv. descflbe'd'and employed may be .usedrin various -=kind's"of'enii1l- In addition ;to"being usefulrinprthochromatic and panchromatic.emulsions, "they may also be useddn non-sensitizedemulsionsan d xray emu s on e .'l $d.Wi1? 6nitizin they may be added to theemulsiombefore or a'fter the dyes are added. The -dispersing agents for the il'vfihalides .b reela i i oljoth r colloid such as water-s ub le cellulose,derivatives; e. -g., 'v fi vl I cel i' ese m thy .r sl u e i boxydxy' cellulose, low acet I lue cellulose acetate, and amaz employed in gelatin vinyl "acetal'dehyde' hydrolyzed cetate r n i's derivatives, e. 11u1oe tate,'the lowerfatty cludingsimpleand riiix lose, and the lilef as" an port for thesensitive emulsionda'yer rorin a-n intermediate layer between ithesensitive-emulsion layer and the -support;suchras?the-baryta' coati s common y used i :rz fi a tapers, or v t d in a protectivelayer 2 s he twi ts?'e fiaqa0 h -Qt e Wise he 9t. ra l ;e m te-is! sy- :b

'l" "1561" or alcol'i'ol water solution graphic mate v As shown where R represents a member selected from the class consisting of amino and methylamino, R1 represents a member selected from the class consisting of amino, methylamino and mercapto groups, and R2 represents a member selected from the class consisting of amino and methylmercapto groups.

2. A photographic material comprising a base and a light-sensitive silver-halide emulsion carried thereby, said photographic material containing, in fog inhibiting amount, a 1,3,5-triazine having the formula:

3. A photographic material comprising a base and a light-sensitive silver-halide emulsion carried thereby, said photographic material containing, in fog inhibiting amount, a 1,3,5-triazine having the formula:

s-cH,

4. A photographic material comprising a base and a light-sensitive silver-halide emulsion carried thereby, said photographic material containing, in fog inhibiting amount, a 1,3,5-triazine having the formula:

5. A photographic material comprising a lightsensitive silver-halide emulsion containing, in fog inhibiting amount, a 1,3,5-triazine having the general formula:

whe e R represents a m mber selected from the 6 class consisting of amino and methylamino, R1 represents a member selected from the class consisting of amino, methylamino and mercapto groups, and R2 represents a member selected from the class consisting of amino and methylmercapto groups.

6. A photographic material comprising a lightsensitive silver-halide emulsion containing, in fog inhibiting amount, a 1,3,5-triazine of the formula:

'7. A photographic material comprising a lightsensitive silver-halide emulsion containing, in fog inhibiting amount, a 1,3,5-triazine of the formula:

Nit-on,

cm-nrr-c N S-CH.

8. A photographic material comprising a lightsensitive silver-halide emulsion containing, in fog inhibiting amount, a 1,3,5-triazine of the formula:

9. A photographic gelatino silver-halide emulsion containing from about 0.1 mg. to about 50 mgs. per liter of emulsion of a 1,3,5-triazine of the formula:

10. A photographic gelatino silver-halide emulsion containing from about 0.1 mg. to about 50 mgs. per liter of emulsion of a 1,3,5-triazine of the formula:

11. A photographic gelatino silver-halide emulsion containing from about 0.1 mg. to about 50 mgs. per liter of emulsion of a 1,3,5-triazine of the formula:

FRITZ DERSCH,

references 01 ted, 

